1. Field of Invention
The present invention relates to substituted azoanthracene derivatives and intermediates for the preparation thereof. The substituted azoanthracene derivatives and associated intermediates may be useful for the preparation of pharmaceutical compositions for the treatment or prevention of diseases, disorders, and conditions wherein modulation of the human GLP-1 receptor is beneficial.
2. Description of Related Art
Diabetes mellitus type 2 is a metabolic disorder where the disease progression may be characterized by one or more of peripheral tissue insulin resistance, hyperglycemia, islet b-cell compensation, hyperinsulinemia, dyslipidemia, increased liver gluconeogenesis, and ultimate loss of b-cell mass and function. The pathophysiological consequences of aberrant glucose and lipid metabolism are toxicity to organs such as the kidney, eye, peripheral neurons, vasculature and heart. Thus, there is a need for agents that may delay disease progression by improving glycemic control and by improving b-cell mass and function.
Glucagon-like peptide-1 (GLP-1) is a member of the incretin family of neuroendocrine peptide hormones secreted from L-cells of the intestine in response to food ingestion. GLP-1 has multiple metabolic effects that are attractive for an anti-diabetic agent. A key function of GLP-1 is to activate its receptor, GLP-1R, on the pancreatic b-cell to enhance glucose-dependent insulin secretion. Positive metabolic benefits of GLP-1 may include, but are not limited to, suppression of excessive glucagon production, decreased food intake, delayed gastric emptying, and improvement of b-cell mass and function. The positive effects of GLP-1 on b-cell mass and function offers the prospect that GLP-1-based therapies may delay early-stage disease progression. In addition, a GLP-1 agonist may also be useful in combination therapies, such as with insulin in patients with type I diabetes. Unfortunately, the rapid proteolysis of GLP-1 into an inactive metabolite limits its use as a therapeutic agent.
Validation of GLP-1R agonists as a therapeutic modality was achieved by Exendin-4 (Byetta® (Amylin Pharmaceuticals, Inc.)), a peptide GLP-1 receptor agonist recently approved in some countries for the treatment of diabetes mellitus type 2. Dosing of Exendin-4 by subcutaneous administration lowers blood glucose and decreases HbA1c levels, which are important biomarker measurements for disease control. Thus, an oral GLP-1 receptor agonist should provide glycemic control while offering the convenience of oral dosing.
GLP-1R belongs to the class B receptor sub-class of the G protein-coupled receptor (GPCR) superfamily that regulates important physiological and pathophysiological processes. In addition to the seven transmembrane domains characteristic of all GPCR family members, class B GPCRs contain a relatively large N-terminal domain. It is believed that the binding and activation of these receptors by large natural peptide ligands require both the N-terminal domain and the transmembrane domain of the receptor. The identification of low molecular weight non-peptide molecules that bind and activate class B GPCRs has proven to be difficult.
Because peptides, such as GLP-1, may lack sufficient oral bioavailability for consideration as oral drug agents, small molecule modulators of GLP-1R with oral bioavailability are desired. The present invention describes a class of compounds that modulate GLP-1R.